Monochramtic x-ray diffraction data were collected from several proteins under high pressure (5-20 atm) xenon gas. Several useful Xe derivatives were formed using a simple pressure cell developed by M. Stowell. This methodology (pressurization) has the potential to be developed into a more general and simple method of making heavy atom derivatives and beamline 7-1 is currently being equipped with apparatus to routinely allow user groups to make use of this technique.